1. Field of the Invention
The present invention relates to medical techniques, in particular, to apparatus and methods used in minimally invasive vascular surgery using grafts for eliminating occlusion of blood vessels or stent-grafts for preventing rupture of abdominal aorta, as well as to methods for their location and fixation. More particularly, the present invention relates to methods and apparatus for securing intravascular devices, such as grafts or stent-grafts, to the walls of blood vessels in direction from inside these vessels to their outer surface.
2. Description of Related Art
Occlusion of great blood vessel resulting from formation of calcic or adipose deposits on their inner walls, or from thrombogenesis causes deterioration of blood supply to most important organs, such as the heart and brain, and to such dangerous situations for the patient, as infarction or insult.
To prevent occlusion of great blood vessels, in modern medicine there are widely used different methods of centura of main blood vessels based on minimally invasive surgery. In the course of centura, inside the main blood vessel, succesively, under X-ray control, there is introduced a guide, and over the latter a catheter with a balloon at the free end. When deposits of essential volume or a thrombus is detected inside the blood vessel, the balloon is inflated by pressure of fluid, so that the corresponding portion of the vessel expands and opens. In case it turns out to be insufficient, and the lumen in the blood vessel remains narrow, there is inserted inside the corresponding portion of this blood vessel a guide with a balloon, carrying on its outer surface a stent in compressed state. When liquid is delivered inside the balloon under pressure, the stent deploys, separates from the balloon and takes the desired position inside the blood vessel. All these manipulations are carried out under X-ray control. Fixation of the stent on the walls of a blood vessel is performed via elastic forces of material the stent is made of, the stent is usually shaped as a spring or has elastic members bearing up against the blood vessel wall or hooking thereon.
When the location of a stent for elimination of narrowing or occlusion of a blood vessel is insufficient, a surgical operation is performed for suturing in a natural or synthetic graft.
An aortic aneurysm (or its rupture) is a most common form of arterial aneurysms. It is a very common type of deteriorating disease affecting the ability of a lumen to conduct fluids and may be life threatening. The aortic aneurysm is a ballooning of the wall of an artery resulting from the weakening of the artery's wall due to disease or other conditions. Left untreated, the aneurysm will frequently rupture, resulting in loss of blood trough the rupture—the condition, which often leads to death.
The aorta is the main artery, which supplies blood to the circulatory system. The aorta arises from the left ventricle of the heart, passes upwards and bends over behind the heart, and passes down through the thorax and abdomen. Among other arterial vessels branching off the aorta along its path, the abdominal aorta supplies two side vessels to the kidneys, the renal arteries. Below the level of the renal arteries, the abdominal aorta continues to about the level of the fourth lumbar vertebrae (or the navel), where it divides into the iliac arteries. The iliac arteries, in turn, supply blood to the lower extremities and perineal region.
It is common for an aortic aneurysm to occur in that portion of the abdominal region between the renal arteries and the iliac arteries. This portion of the abdominal aorta is particularly susceptible to weakening, resulting in an aortic aneurysm. Such an aneurysm is often located near the iliac arteries. An aortic aneurysm larger than about five centimetres in diameter in this section of the aorta is ominous. Left untreated, the aneurysm may rupture, resulting in rapid, and usually fatal, hemorrhaging. Typically, a surgical procedure is not performed on aneurysms smaller than five centimetres because no statistical benefit exists in performing such procedures.
Aneurysms in the abdominal aorta are associated with a particularly high mortality rate; accordingly, current medical standards call for urgent operative repair. Abdominal surgery, however, results in substantial stress to the body. Although the mortality rate for an aortic aneurysm is extremely high, there is also considerable mortality and morbidity associated with open surgical intervention to repair an aortic aneurysm. This intervention involves penetrating the abdominal wall to the location of the aneurysm to reinforce or replace the diseased section of the aortic aneurysm. A prosthetic device, typically a synthetic tube graft, is used for this purpose. The graft serves to exclude the aneurysm from the circulatory system, thus relieving pressure and stress on the weakened section of the aorta at the aneurysm.
Beside synthetic grafts, there are developed and widely used all over the world particularly to prevent the rupture of the aorta wall intravascular devices of “stent-graft” type. They are inserted and positioned similar to stents. Fixation of a stent-graft on aorta walls is performed via elastic forces of the material of the stent-graft itself which usually has springy elements bearing up against the blood vessel wall or hooking thereon. When the forces of elastic or springy elements of the stent-graft are insufficient for its fixation in a blood vessel, the stent-graft may be displaced from the assigned position and moved along the aorta under the action of blood flow and peristelsic oscillations of walls of this blood vessel, and that is very dangerous for the patient.
Repair of an aortic aneurysm by surgical means is a major operative procedure. Substantial morbidity accompanies the procedure, resulting in a protracted recovery period. Further, the procedure entails a substantial risk of mortality. While surgical intervention may be indicated and the surgery carries attendant risk, certain patients may not be able to tolerate the stress of intra-abdominal surgery. It is, therefore, desirable to reduce the mortality and morbidity associated with intra-abdominal surgical intervention.
In recent years, the common repair means is to deploy a stent-graft within the lumen of the affected aorta in the region of the aneurysm. These methods and devices have been developed to attempt to treat an aortic aneurysm without the attendant risks of intra-abdominal surgical intervention. Among them are inventions disclosed and claimed in Parodi, Juan C. et al., WO 010487A1 for Graft Device for Treating Abdominal Aortic Aneurysms and its patent family, including U.S. Pat. Nos. 5,219,355, 5,522,880, 5,571,171, 5,643,208, 5,683,452, 5,693,087, 6,102,942, EP 461791A1, EP 809980A3, EP 903118A2, EP 903119A3, EP 903120A3 etc.
Parodi discloses a stent-graft device for locating inside an aorta affected by an aneurysm causing the aorta to have an inner diameter smaller than the sum of inner diameters of the iliac arteries. The graft has an upper main tubular portion dividing into two pending graft limbs capable of accommodating together within the restricted inner diameter of the aorta without the restriction of the aorta affecting the diameter of the limbs. The limbs have respective distal end portion having diameters larger than the diameters of the graft limbs so as to be accommodated and retained within the iliac arteries Parodi's stent-graft is inserted using a tubular device also disclosed in his patent.
In other Parodi's patents there are disclosed stent-graft designs having a metal wire frame collapsible to a minimal size sufficient to insert the stent-graft into the artery through a puncture in its wall and expandable inside the aorta to a required size under the action of a radial force, such as a balloon. This frame is covered by a sheath which can contract and expand together with the frame under the action of external forces. Aforesaid stent-grafts are provided with means for mechanical fixation to the walls of the aorta or iliac arteries. Among those means we find balloon cuffs of a special shape at the stent-graft ends, see WO 010487A1, U.S. Pat. No. 5,522,880, U.S. Pat. No. 5,219,355, various hooks, elements shaped as scales, spirals and similar elements designed for fixation on the wall of the aorta or artery, see U.S. Pat. No. 5,911,733 Endovascular Expander of a Non-migrant Positioning, EP 948945A2 Endovascular Prosthesis with Fixation Means.
The problem of fixation of stents and stent-grafts inside the aorta and iliac arteries is PARTIALLY solved by other inventors likewise.
Lindenberg, Josef in EP 711135A1 discloses a stent with an improved anchorage in a vessel. The stent can be expanded from a radially contracted insertion state into a radially expanded positioning state such that in the radially expanded state at least one end has a larger radial extension than the remaining main body of the stent.
Samuels in U.S. Pat. No. 5,423,851 discloses a method and apparatus for affixing an endoluminal device to the walls of tubular structures within the body which utilizes incremental inflation of a balloon cuff to deploy radially projecting barbs attached to the cuff within plurality of recesses.
Kugler, Chad disclose in their patent WO 19943A1 a stent-graft comprising radially expandable portions attached to one another and anchored to the aorta walls by a radial force. This stent-graft can bend to match the aorta longitudinal section by relative angular displacement of its portions.
Houser, Russel in WO 15144A1 discloses a system and components for treating aortic aneurysms includes a reinforcing graft and combinations of fittings and rings for securing the graft to a host vessel, to branch vessels, for example the iliac, and renal arteries.
Edwin, Tarun et al., disclose in EP 868154A1 a structurally supported graft having a support structure with strain relief sections containing an internal surface, an external surface, or a wall thickness of a tubular graft member. The structural support forms a spiral about the tubular graft.
Numerous suggestions of stent-graft inventors present various hooks and anchor members, integral or not integral with the stent-graft frame to fixate the latter inside the aorta or iliac arteries. Such suggestions are disclosed in U.S. Pat. No. 6,015,431, EP 747020A2, EP 701800A1, EP 657147A2, EP 466518A2, U.S. Pat. No. 5,669,936, U.S. Pat. No. 6,004,347, U.S. Pat. No. 5,733,325, U.S. Pat. No. 5,104,399, U.S. Pat. No. 6,030,413.
All the above-mentioned inventions have, in our opinion, a common drawback, which consists in the fact that the stent-grafts fixation on the inner walls of the aorta and iliac arteries is not reliable enough and bring to many complications. Therefore, under the action of blood flow and peristaltic oscillations of artery walls, stent-grafts are displaced from their proper positions, which may have grave consequences for the patient and result in his death because of the aorta rupture.
3. The Prior Art
Closest to the present invention are inventions disclosed and claimed in Taheri, Syde, U.S. Pat. No. 5,843,169 for Apparatus and Method for Stapling Graft Material to a Blood Vessel Wall while Preserving the Patency of Orifices and inventions disclosed and claimed by Tanner, Howard, in U.S. Pat. No. 5,944,750 for Method and Apparatus for the Surgical Repair of Aneurysms, U.S. Pat. No. 5,957,940 for Fasteners for Use in the Surgical Repair of Aneurysms and U.S. Pat. No. 5,997,556 for Surgical Fastener.
Taheri, Syde in U.S. Pat. No. 5,843,169 discloses an apparatus for stapling graft material to a blood vessel wall comprising a stapling device, a balloon catheter, a sheath, and an inflation means.
The apparatus design suggested by Tahery is, in our opinion, inoperative as the radial force generated by a balloon is inadequate to insert a securing member shaped as a nail into the wall of the aorta or artery. It is especially unlikely if the wall of the aorta or artery is covered with calcium plaques.
Tanner, Howard in U.S. Pat. No. 5,944,750 discloses an attachment assembly and repair graft for securing to repair a vessel having an aneurysm therein. The attachment assembly comprises an attachment cuff such that the graft is not dimensionally dependent upon the size of the vessel. The apparatus also comprises a visualization apparatus for real time direct viewing of an interior of a vessel. A penetration apparatus is disclosed for use in forming treatment specific holes in a potentially calcified vessel wall, which facilitates thereafter the securing of the graft and attachment assembly to the vessel wall. An introducer sheath device is also disclosed that comprises a sealing assembly for preventing the loss of blood from the vessel during the insertion and subsequent removal of surgical components during the surgical procedure.
In U.S. Pat. No. 5,957,940 and U.S. Pat. No. 5,997,556, H. Tanner also discloses fasteners for use during a surgical procedure for securing surgical components to the blood vessel wall under a compressive force. According to the inventions, the fastener assemblies are shaped as a coiled spring or spiral or plurality of entwined coil springs or ring type fasteners including a plurality of rings.
All the described inventions by Howard Tanner have, in our opinion, a complicated and not adequately reliable design and limited functional possibilities. So, in particular, the apparatus for setting the securing elements cannot be brought in operative position inside iliac arteries having a small lateral diameter. Because of limited space it is impossible to bend the end of the apparatus working head for setting the securing elements in the stent-graft wall. The efficiency of this apparatus for drilling holes in the walls of the stent-graft, aorta and iliac arteries is doubted, especially if these walls are calcified and covered by calcium plaques. In general, we think that the apparatus presented by Howard Tanner can be used only inside the aorta and not inside iliac arteries. As far as the suggested securing elements are concerned, we believe that their fixation in the inner walls of the aorta and iliac arteries is not reliable enough. Therefore, under the action of blood flow and peristaltic oscillations of artery walls, the stent-graft may be displaced from its proper position, which may have grave consequences for the patient and may result in his death due to the aorta rapture.
And finally, there are known devices developed in France by Thierry Richard, Eric Perouse et al., such as “Surgical staple inserter”, see U.S. Pat. No. 5,346,115; WO 9217117; EP 0533897 and “Surgical staple for tissue”, see Pat. FR 2746292.
U.S. Pat. No. 5,346,115; WO 9217117; EP 0533897 describes a surgical staple inserter for joining two ducts such as a blood vessel and blood prosthesis. The staple inserter ejects staples in a radial direction relative to the axis of the ducts. In one embodiment, it includes a staple holder surrounded by the prosthesis and containing a series of staples arranged in at least one ring. All the staples are ejected simultaneously. The staple inserter also includes an anvil outside the organic duct, and a device for spacing apart the anvil and the staple holder in relation to their relative working position. Projections hold he prosthesis in place during the insertion of the staple holder into the ducts.
This device is essentially complicated in design, and the main drawback of it is that it is impossible to bend the ends of staples when they are extended from the device body outside, through the prosthesis and wall of the blood vessel. Therefore it is necessary to provide the device with anvils located outside the operated blood vessel, which makes the device itself and the whole surgical procedure for setting a stent-graft considerably more complicated and expensive.
Pat. FR 2746292 describes a surgical staple, which has a circular spiral formed of metallic wire. It extends on a complete spiral, which is augmented over part of its length. The staple can have a barbed end. The device for these staples inserting comprise a guide tube, extending towards the front by an inwardly curved section with a guide channel. At least a section of metal wire moves in the guide tube. A pusher moves the wire section towards the distal end of the guide tube.
This device also has some essential drawbacks. So it is a difficult procedure to set the staples, as it is necessary to achieve very precise positioning of the device relative to the prosthesis wall. It is impossible to set simultaneously several staples with this device design. Besides, an essential part of staples project inside the prosthesis, which may result in accelerated thrombogenesis in this inner lumen of the prosthesis.
In general, at present, the authors of the present invention have no information on any methods and apparatus for fixation of grafts and stent-grafts on the walls of a blood vessel from inside this vessel, which are developed, ready for full-scale production and applied in real life in minimally invasive surgery.
An object of the present invention is to provide reliable and relatively simple means for securing a graft, stent-graft or other intravascular devices to the wall of the aorta, iliac arteries or other arteries, in particular, a new and improved method for stapling and stapling apparatus based on this method.
Another object of the present invention is to provide suturing of the prosthesis to a blood vessel simultaneously over the entire perimeter of the connection, and assuring necessary strength and leak-proofness of this connection, including even such hard-to-reach spots as the aorta neck or the area directly under the renal arteries.